package stasckdemo;

import java.util.Stack;

class MyQueue1 {

    private Stack<Integer> s1;
    private Stack<Integer> s2;
    public MyQueue1() {
        s1 = new Stack<>();
        s2 = new Stack<>();
    }
    
    public void push(int x) {
        s1.push(x);
    }
    
    public int pop() {
        if (empty()) {
            return -1;
        }
        if (s2.empty()) {
            while(!s1.empty()){
                Integer push = s2.push(s1.pop());
            }
        }
        //
        return s2.pop();
    }
    
    public int peek() {
        if (empty()) {
            return -1;
        }
        if (s2.empty()) {
            while(!s1.empty()){
                Integer push = s2.push(s1.pop());
            }
        }
        //
        return s2.peek();
    }
    
    public boolean empty() {
        return s1.empty() && s2.empty();
    }
}